Signaling system



0. C. LEVY S IGNALING SYSTEM May 8, 1934.

3 Sheets-Sheet 1 Inuen car- Decal" 1:. Leu

Filed 001. 5, 1930 y 8, 1934- o. c. LEVY 1,957,657

SIGNALING SYSTEM Filed Oct. 3, 1930 3 Sheets-Sheet 2 -ITIUEFL E1" UECEI" LELHj May 8, 1934. o. c. LEVY SIGNALING SYSTEM Filed 001?,- 3, 1930 3 Sheets-Sheet 3 Patented May 8, 1934 UNITED STATES PAT I-i T F FICE SIGNALING SYSTEM Delaware Application October 3,

12 Claims.

This invention relates in general to signaling systems, but more particularly to police registration and signaling systems of the type in which the patrolman in making his rounds informs a central station or" his whereabouts by operating mechanism at the substations which are distributed over his route. More particularly the invention relates to a system comprising a central office connected to a plurality of outlying substations, together with means at the central office for supervising, directing and controlling the signaling and transmission of intelligence to and from the outlying substations.

The principal object of the invention is to provide improved equipment and circuits for a signaling system which reduces the installation and maintenance cost thereof without detriment to the reliability and usefulness of the system.

A further object of the invention is to provide means for enabling a central station supervisor to connect with any line in the system; to provide means to either audibly or visually signal a particular patrolman or all patrolmen in accordance with a predetermined code, and to provide talking circuits so that the supervisor may converse with the patrolman so as to give him directions and instructions.

A further object of the invention is to provide means at the central station whereby the supervisor may connect any patrol line with another station, such as a captain or police official, and provide means for connecting the captain or the central ofiice supervisor with the telephone exchange system of the town or city in which the signaling system -is installed.

The above objects and other features not specifically mentioned will be apparent in the detailed description of a preferred embodiment of the invention, which is illustrated in the accompanying three sheets of drawings by means of the usual schematic circuit diagrams.

The drawings comprising Figs. 1, 2 and 3 with Fig. 2 placed immediately below Fig. 1 and Fig. 3 to the right of Fig. l with the corresponding numbered lines in alignment, show sufficient details of the equipment to permit a clear understanding of the invention. Fig. 1 shows the patrol station PL connected to the central ofiice and terminating in the line equipment LS which is individual to the patrol station PL. The supervisors telephone OP is adapted, by means of certain keys shown in the drawings, to be connected in a number of different ways with other telephones as will be pointed out. Fig. 2 discloses the captain or police ofiicials telephone B and 1930, Serial No. 486,191

other keys and equipment by means of which the telephone B may be connected by the supervisor to either the trunk line 239 and 240 extending to the telephone exchange or for other purposes as will be apparent. Fig. 3 discloses the control switches S1 and S2 and the code sender switch CS, by means of which the supervisor at the central office may transmit a particular code number any number of times, to signal the patrolman at the station PL or any other station.

Referring now more particularly to the drawings a brief description of the apparatus and equipment employed will be pointed out. The patrol station PL is connected over conductors 2 and 3 with the individual line equipment LS at the central office. Each patrol substation comprises the usual talking and signaling instrumentalities and in addition the visible and audible signaling devices L-1 and BL are provided. The recording device PR associated with the individual line equipment LS permits a record of the patrol station PL to be made when the patrolman reports periodically. The remaining equipment of Fig. 1 including the various keys is common to all of the patrol lines in the system.

In Fig. 2 the trunk line 239 and 240 extending to the city telephone exchange, may be connected by the supervising operator to either the captains telephone B or to the operators own telephone OP by means of the various keys disclosed in this figure and in this connection the various lamp signals disclosed in Fig. l and also in Fig. 2 provide the usual supervision of all telephone connections.

In Fig. 3 the control switches S1 and S-2 are of well known construction such as illustrated and described in the book Automatic Telephony by Smith and Campbell, page 94, published by the McGraw-I-Iill Book Company. In general these switches comprise a wiper 328 which is adapted to be rotated over a plurality of bank contacts under control of the stepping magnet 325. After having been operated the wiper is restored to normal position under control of release magnet 326. The code sender switch CS is likewise of well known construction and is described in the above mentioned book on page 51. This switch comprises a pair of wipers 382 and 383 adapted to be rotated in a forward direction only under control of the rotary magnet 380, and after having 105 been operated the number of times desired the wipers are automatically rotated in a forward direction over the bank contacts to their normal position. The control switches S1 and 8-2 are adapted to be operated under control of the associated group of relays to the left of these switches which are in turn controlled from the calling device CD of the operators telephone circuit by means of impulses. The control switch S1 is operated in accordance with the first digit or a series of impulses, comprising a code number while the control switch S2 is operated by the second digit of a series. The code sender CS is then adapted to operate its associated wipers to pick up the code number from the banks of the control switches and connect the generator current from the generator G2 to the patrol line 2 and 3 to operate either the visual or audible signal at the station, depending on whether key K6 or key K7 is operated, in order to call the attention of the patrolmen. The two-digit code, it will be understood, may be transmitted to only one police line or to any number desired by the supervising operator.

Having thus described the invention in general a detailed description of the operation of the system will now be pointed out in connection with the various operations performed by the patrol men in traversing their patrol beats and also by the supervising operator in supervising the various telephone or other connections in the operation of the system.

It will first be assumed that the patrolman is traveling on his beat and at predetermined time intervals is required to call in to the central office to indicate that he is on duty, or to receive instructions from the supervising operator if necessary. In accordance with this procedure the patrolman, upon arriving at the street patrol box which is of the usual type, will open the door by means of which this equipment is inclosed and remove the receiver R from the switch hook SW. This action closes a loop circuit extending from the patrol box to the central office, from ground through the upper winding of relay 30 of the individual equipment LS, normally closed springs 38 of key K6, normally closed springs 42 of key K7, normally closed contacts 22 of relay 20, conductor 3, through the transmitter T, receiver R, switch hook springs SW, induction coil N, back over conductor 2, normally closed contacts 26 of relay 20, normally closed springs 45 of key K7, normally closed springs 40 of key KG, through the lower winding of relay 30, to battery. Relay 30 is thereby energized over this circuit and at front contact and armature 31 prepares a circuit for relay 20 which is opened at another point at back contact and armature 32. At front contact and armature 33 a circuit is completed for the individual line lamp L2 from ground at armature 24 and its back contact. The illumination of lamp L2 indicates to the supervisor at the central ofiice the fact that the patrolman is reporting in from his patrol box. A branch of the circuit for lamp L2 extends by way of front contact and armature 34 through the winding of the recording magnet PR which is individual to the patrol station PL. This recording magnet upon operating its armature prints an impression on a moving tape of the number of the line the date and time of the call, and other necessary information required. The printing recorder PR is of well known construction and comprises the magnet PR which is individual to each patrol line and other equipment which is common to all of the lines. Recording mechanism of this type is disclosed in an application of H. Sengebush, Serial No. 417,280, filed December 30, 1929.

If at the time the patrolman is reporting to the supervisor at the central station, she desires to give him certain instructions, she will note by the illumination of the lamp L2 that the patrolman is reporting and immediately afterward operate her key KG or K7, either of which will perform the same function at this time. Relay 30 will be operated, it will be remembered, when the patrolman reports in, and at front contact and armature 31 prepare a circuit for relay 20 which is completed through the operation of key K6 from gl'Olllld on contact spring 36, through the upper winding of relay 20, to battery. Relay 20, upon energizing, closes a locking circuit for itself by way of its front contact and armature 23. At the back contact of armature 24 relay 20 opens the circuit for the lamp L2 thereby extinguishing it. As a further result of the energization of relay 20, armature 21 engages contact 22 thereby breaking the normally closed contacts and closing the normally open contacts. A similar action takes place when armature 25 engages contact 26. The patrol line conductors 2 and 3 are now connected directly to the supervisors telephone circuit OP by way of conductor 3, contact 22, condenser 27, common conductor 47, armature spring 52 and normally closed spring of key K2, the normally closed spring and armature spring 54 of key KB, conductor 67, through the operators telephone circuit OP including the induction coil N closed switch hook springs SW, back over conductor 68, armature spring 56 and normally closed spring of key K 4, armature spring 55 and normally closed spring of key K3, normally closed spring and armature spring 53 of key K2, common conductor 46, to the condenser 28. Talking current for the operators telephone set OP is furnished from ground and battery through the windings of relay 105 which are connected to the normally closed springs of key K2. Talking current for the patrol line is furnished from relay 30 at armatures 21 and 25. The supervisor may now converse with the patrolman on the line and supply him with any necessary instructions. When the supervisor desires to terminate the conversation she restores the key Kfi so that the locking circuit for relay 20 will be opened at contacts 36. Relay 20 upon restoring, disconnects the operators telephone circuit OP at armatures 21 and 25. At armature 24 the circuit for the lamp L2 is again completed, so that it now serves as a supervisory lamp to indicate that the patrolman at the patrol station PL has his receiver still off of the switch hook. Upon restoring the receiver R to the switch hook SW, the loop circuit extending over the patrol line conductors 2 and 3 will be interrupted and relay 30 will thereby deenergize and restore. At armature 33 the circuit for the line lamp L2 is opened.

In certain instances the patrolman may desire to signal the supervisor for particular emergency cases, such as riot calls or calls for an ambulance. In this event it is desirable for the supervisor to be immediately notified of the patrolmans desires. The manually operated key P at the patrol station is provided for this purpose. This key may be controlled either by the patrolman operating it manually, or by means of a particular type of lock. In any event the contacts 17 and 18 are held closed for a certain period of time so that a loop circuit at the station is completed from line conductor 2, contacts 1'7, winding of slow-to-operate relay l5, armature 16 and its back contact, contacts 18, and back over the line conductor 3. The com plete circuit to the central ofiice extends through contacts 22, closed springs 42 of key K l, closed springs 38 of key K6, upper winding of relay S to grounc; and from the lower winding of "lay closed springs e0 of key K6, springs of key K7, contacts 26 of relay 20, and the .ine conductor 2. Relay l energizes slowly in this circuit after operating its armature 16 pts its circuit and slowly restores. Re= lay is thereby alternately opens and closes the loop over the line conductors 2 and 3 at its armature 16. I y Eilenergizes over the loop cir wit and alternately energizes and deenergizes, to the opening and closing of armature 16 an its back contacts. At the front contact of mature 33 ground is connected from armature o illuminate the lamp L2. The lamp L2 instead of burning steadily as in an ordinary reporting call from the patrol line, will thereby operate in a flashing manner to signal the super- The supervisor noting the flashing cone. .on 01 the lamp L-2 will respond to this signal by operating either the key K-6 or K-l which in addition to serving as audible and visible signaling keys, act as answering keys.

Ground is thereby connected, for example, from key K6 at its springs 36, through armature 31 and its front contact, through the upper winding of relay 20 b cry. Relay 20 upon energizing, closes a locking circuit for itself at front contact and armature 23, and at armatures 21 and 25 connects the patrol lines 2 and 3 through the condensers 27 and 28, to the common talking conductors to and at extending through keys K-22 and K-3 to the operators telephone circuit 0?. The operator may therefore converse with patrolman on the line and be informed of too nature of the emergency call.

Referring now to Fig. 2 the substation telephone B is ssigned to the captain or other police or cial from whom patrolmen may take orders. s oiiicial may at times desire to converse with cumin patrolmen on their beats at the time they are calling in, and the supervising operator is the contiolling factor in establishing these connections. The removal of the receiver at the substation B by the captain establishes a circuit extending from battery through the winding of relay 200, normally closed armature springs 208 or" key Fri-9, normally closed springs and armature 203 of key K8, through the substation normally closed armature and springs 202 on the upper side of key K8, to ground through the normally closed springs and armature 208 on the upper side of key K9. Relay 200 energizes in this circuit and at its front contact and armature 201 connects ground to the ia p L5 which upon becoming illuminated informs the supervising operator that the capat substation B desires her attention. The supervising operator thereupon operates the key l ----8, disengaging the normally closed contacts from the armature springs 202 and 203 and connecting the telephone at substation B directly onto the conductors 80 and 81. Relay 200, thereby has its circuit interrupted and it retracts its armature 201 to open the circuit to the lamp L-5, which now serves as a supervisory lamp.

The talking circuit between the substation B and the operators telephone circuit 0? is completed over conductors 80 and 81, normally closed springs and 51 of key K-l, through the condensers 107 and 108, normally closed springs 54 and 55 of key K3, one side or" the circuit extending through normally closed springs 56 of key K4, and then over conductors 67 and 63 to the operators telephone circuit OP. Talking battery is furnished to the operators circuit 0? from the windings of relay 105 on one side of the condensers 107 and 108, and on the opposite side of the condensers the talking cur'ent for the substation B is furnished through the windings of relay 100. Both of these relays energize and at front contact and armature 101 relay 100 prepares a circuit for the supervising lamp L-3, whil at armature spring 106 and its back contact relay 105 opens a point in the circuit of this lamp. The captain now engages in conversation with the supervisor and informs him of desire to be connected to a particular patrol station, for example, the patrol station PL.

Ii, for example, the patrolman at the box PL is at this time making his usual time report or call the supervisor merely operates the key K 6 which has been pointed out, operates the relay 20 to connect the patrol station PL with the line equipment LS. The key K2 is then operated so that the armature springs 52 and 53 will disengage their normally closed springs and make contact with normally open springs. This action disconnects the operators telephone GP and the relay 105 from this circuit. Belay 105 at armature 106 closes the circuit of superviscry lamp L-3. The operator then restores the key K-8 allowing relay 10-0 to restore and extinguish lamp 1P3, and operates he key K-9. The captains telephone B is now connected to the patrol line PL over the following circuit: one side of the line of the telephone B, armature spring 202 and its normally closed spring of key K8, armature 208 and its normally open spring of key K9, back contact and armature 221 of relay 220, conductor 83, normally open spring and armature spring 52 of operated key K--2, common conductor 4'7, condenser 27, operated contact 22 of relay 20, the line conductor 8 of the patrol line PL, through the talking instruments of the patrol line, back over line conductor 2, operated closed contacts 26 of relay 20, condenser 28, common conductor 16, armature and normally open spring 53 of key K-Z, conductor 82, armature 222 and its back contact, armature spring 208 and its normally open spring on key K9, normally closed spring and armature 203 of key K8, through the captains telephone B. The talking battery for the patrol line PL is furnished as before, through the windings of relay 30, while the talking current for the captains line B is fed through the upper and lower windings of relay 210 which is connected to armature springs 221 and 222 of the above traced circuits.

Relay 210 at its armature 211 and back contact opens a point in the circuit of supervisory lamp L- l to serve as a disconnect signal for the captains telephone B while at contact 204 of operated key K9 the circuit for the lamp L4 is prepared. Conversation may now proceed between the patrolman on the patrol line PL and the captain at the telephone substation B. Restoring the receiver on the switch hook by the captain at the station E opens the line circuit and causes the supervisory lamp I z-4 to become operated due to the deenergization of relay 210 which completes the circuit for the lamp L-4 at armature 211 and its back contact. When the patrolman at the station PL restores his receiver the line relay 30 will deenergize thereby restoring armature 33 to its back contact to light the lamp L2, from ground on armature 24 and front contact of relay 20. The supervisory operator noting the illumination of lamp L--2 restores the key K4, K2 and K9, so that the equipment is again in normal position. Key KG opens the locking circuit for relay 20 at armature springs 36.

It will be appreciated from the foregoing that the captains telephone B may be connected by the supervisor with any one of the patrol stations, such as PL in the system, by operating the individual key, such as key KG associated with the desired patrol line, and if desired the captain may be connected with any number of patrol lines at the same time in this manner.

Should the supervising operator at any time wish to communicate with the captain at the telephone station B, she operates keys Kl and KS, thereby closing the armature springs 50 and 51 upon their normally open springs and projecting ringing current from the generator G1 over conductors and 81, through operated springs and armatures 202 and 203 to the line and signaling bell of the telephone at substation 13. The supervisor after having projected the ringing current over the conductors 80 and 81 for a short time, will restore her keys Kl and key K--8. The captain upon answering the call removes his receiver from the switch hook and completes the circuit for relay 200, through the normally closed springs of key K8 and key K9, as has been previously pointed out. Relay 200 at its armature 201 closes the circuit to the answering lamp L5 to indicate that the captain has answered.

It is occasionally necessary that the captain at the telephone B call other private telephones in the telephone exchange system. For this pmpose the trunk line 239 and 240 extending to the telephone exchange is provided. This telephone exchange may be either of the automatic or manual type. In making a call of this kind the receiver is removed in the substation B, thereby energizing the relay 200 and illuminating the lamp L5 to attract the attention of the supervising operator. The operator will cut in on the telephone line B by operating the key K8 over a circuit which has been previously traced. After being informed that the captain at the telephone station B desires to establish a connection over the trunk line 239 and 240 to a particular telephone in the city exchange, the operator restores the key K8 and operates the key K9. The operation of key K9 disconnects relay 200 and permits the lamp L5 to go out. At this time or previous to the operation of key K-9 the supervisor operates the key K10. This extends the telephone circuit from the telephone B directly to the trunk conductors 239 and 240, through closed springs 218 and 219. At springs 214 a circuit is completed for relay 225, which upon operating at armatures 226 and 227 opens a point in the circuit for the ring-up relay 230. At springs 223 a circuit is completed for the relay 220, which upon operating opens its armatures 221 and 222 from its back contacts so as to disconnect the operators telephone set OP, extending over conductors 82 and 83, from this connection, and also prevent the energization of relay 210 at this time. The captains telephone set B is then placed in connection with any telephone line he may desire by the telephone operator at the telephone exchange in the usual manner.

Should the supervising operator desire to impart certain information to the captain while he is connected to the exchange, she may do so by operating the key Kll which at its springs 234 places a shunt across the conductors 239 and 240 to hold up the existing connection to the telephone exchange. She operates the key K-8 so that her telephone circuit may be extended over conductors 80 and 81, through springs 202 and 203 to the telephone B. At springs 235 the lamp L-6 is illuminated by key Kll to inform the operator that she is holding up the connection over the trunk line.

An alternative method of establishing a con nection between the captains telephone B and the telephone exchange is for the supervising op erator to establish a connection from the telephone set OP, and after the connection has been established, transfer it over to the line extending to the captains telephone. In order to do this the supervisor first operates the key Kl2 which at springs 23'? and 238 connects conductors 84 and 85 to trunk lines 239 and 240. The key K3 is likewise operated so that it extends the conductors 84 and 85 through its normally opened springs 54 and 55 over conductors 6'7 and 68 to the telephone circuit OP.

The relay 205 operates whenever a connection is established to the telephone exchange from the captains telephone B and opens a point in the circuit of lamp L4 at armature 208 and its back contact. This relay 205 restores whenever either the connection to the exchange is terminated or the captain replaces his receiver and it completes the circuit for the lamp L4 to inform the supervisory operator to restore her keys K9, 31-10 and any others that may be operated at this time, which were used in establishing the connection.

When the operator at the telephone exchange desires to establish communication with the supervising operator of the police signaling system, ringing current from the exchange is transmitted over the trunk conductors 239 and 240, and extends from conductor 239, back contact and armature 226, back contact and armature 231, upper winding of ring-up relay 230, ringing condenser 229, armature and back contact 227 and then out over conductor 240. Relay 230 upon energizing locks itself energized at its front contact and armature 232, from ground on back contact and armature 228; at front contact and armature 233, a circuit for the lamp L7 is completed. At armature 231 the original circuit of relay 230 is opened. The supervising operator noting the illumination of the lamp L7 operates the keys K12 and K3. Key K12 closing springs 236 and completing the circuit for the cutoff relay 225. Relay 225 upon energizing, at its armatures 226 and 227 and their back contacts, opens a further point in the circuit for the ringup relay 230. At armature 228 the locking circuit of relay 230 is opened and it thereupon deenergizes. Relay 230 upon deenergizing opens the circuit for the lamp L'? at armature 233. As a further result of the operation of the key K12 the trunk conductors 239 and 240 are extended through the key K12 by way of springs 237 and 238, to the conductors 84 and 85; conductor 84 extending through normally opened springs 55 of key K3, normally closed springs of key K-4, to the operators telephone circuit over conductor 68. The other side of the circuit extending from conductor 85, normally opened springs 54 of key K3, and over conductor 67. The supervising operator can now talk to the operator at the telephone exchange and may transfer the call to the captain at the substation B by restoring her keys K-l2 and K3 and operating keys K9 and K--10.

So far the description has dealt with the manner in which the supervising operator may control the establishment of a connection to and from the patrol line PL, the captain at the extension telephone 13, and also the manner in which communication with the telephone exchange may be established by the supervising operator. A description will now be given of the means whereby the supervising operator may signal a particular patrolman on a police line or signal all of the patrolmen, by means of special code signals either audible or visible. In this connection the equipment illustrated in Fig. 3 will be utilized.

The signaling equipment at the patrol station PL consists of a lamp L--l and a loud ringing bell BL. The lamp L-l is operated by means of the alternating current relay 5 which is connected through the condenser 7 to the line conductor 3. The bell BL is operated by the alternating current relay 10 which is connected through condenser 8 to the line conductor 2. The current for operating these signals is either a local source of battery BA or may be a commercial source of alternating current. When the supervising operator desires to signal the patrolman on line PL she may do so by either operating the lamp l -1 or the loud ringing bell BL. The key K-6 when operated establishes a circuit condition for operating the audible alarm BL, while the key K-l when operated establishes a circuit condition for operating the lamp L-l.

Assume that the supervising operator desires to signal the patrolman by means of the signal lamp L-l, in accordance with the call number 64 she will operate the key K--7 thereby preparing a circuit extending from the common si naling conductor 75 of Fig. 3, lower winding of ringing relay 2:), back contact and armature 32, springs 43 and 42 of operated key K- I, normally closed contacts 22 relay 20, line conductor 3, condenser 7, through the winding of relay 5 to ground. At springs 44 and 45 key K-V extends ground through normally closed contacts 26 of relay 20, to the line conductor 2. After having prepared the circuit for signaling the pa trolman on the line PL, the supervisor operates the keys K& and K-5. The operation of key K-4 extends the operators telephone circuit OP from the conductor 68, armature spring 56 and spring 57 of key K l, conductor 70, through the upper winding of relay 360, to battery. The other side of the connection extends over the impulse spring 65 of operators calling device CD, conductor 69, armature spring 58 and spring 59 of key K- l, closed springs 60 of key K5, conductor '71, through the lower winding of relay 300, to battery. Relay 300 upon operating, extends ground from its armature 301 and its front contact, through the winding of slow to-release relay 305 to battery. Relay 305 upon operating at its front contact and armature 306, prepared a circuit for the stepping magnet 325 of the contol switch S-l. At the front contact of armature 307, relay 305 prepares a locking circuit for relays 315 and 320, while at the back contact of this armature it prepares the releasing circuit for the release magnets 326 and 331.

The circuits are now in condition to receive the impulses responsive to the operation of the supervisors calling device CD, and each time the calling device CD is operated the contacts 66 will be closed so as to shunt out the trans mitter T and receiver R during the transmission of the impulses. Responsive to the first digit of the calling number which is 6, the impulse springs of the calling device CD are operated to open and close a similar number of times, thereby interrupting the circuit for the line relay 300 a corresponding number of times. When relay 3G0 falls back, due to the first interruption of its circuit, it completes a circuit extending from ground on armature 301 and its back contact, armature 356 and its front contact, through the winding of low resistance slowoperating relay 310, normally closed contacts of armature 316, through the winding of the stepping magnet 325, to battery. The stepping magnet 325 upon energizing rotates the wiper 328 one step in a forward direction onto its first bank contact, and at the same time the oif=normal springs 32? are closed and prepare a circuit for the release magnet 326. Series relay 310 energizing in the above circuit, closes a circuit for the lower winding of two-step relay 315 from ground on front contact and armature 311, armature 318 and its back contact, through the lower winding of relay 315 to battery. Relay 315 is so constructed that with its lower winding only energized it can only operate its armature 317 and not armatures 316 and 318. However, when the upper winding of the relay is energized all of the armatures will be operated. In this connection, therefore, with the lower winding energized relay 315 only closes armature 317 on its front contact and prepares the circuit for its upper winding which is at this time short-circuited by ground from armature 311 on one side and ground by way of armature 307 and armature 317 on the other side of the winding.

The remaining impulses of the series generated by the impulse springs 65 of the calling device CD and corresponding to the first digit 6 of the calling number are projected over the line conductors '70 and '71 to repeatedly energize and deenergize relay 300. Relays 305 and 310 because of the copper slugs on their heel end remain energized throughout this series of impulses and the stepping magnet 325 rotates its wiper 328 in a forward direction over the bank contacts until the sixth contact to which conductor 38 1 is connected is reached.

After the transmission of the first series of impulses comprising the digit 6 the supervisor will operate the calling device CD in accordance with the digit 4. However, during the interval between the two digits relay 300 will remain energized and also maintain energized slow-release relay 305. At the back contact of armature 301 the circuit for series relay 310 is interrupted and after a short interval it restores its armature 311 and as a result the twostep relay 315 has its upper winding energized from ground on armature 3G7 and its front contact, armature 317 and its locking contact, through both windings of relay 315 in series to battery. Relay 315 upon energizing. operates its armatures 316 and 318, (31'? having been previously operated) and at front contact and armature 316, a circuit for the steppin magnet 330 is prepared by way of armature 321 and its back contact, while at the back con tact or armature 316 the stepping magnet 325 is disconnected. At the front contact of armature 318, relay 315 prepares the energizing circut for the lower winding of relay 320. Relay 326 is similar in construction to relay 315.

The second digit 4 comprising four impulses is transmitted from the impulse springs 65 of the calling device by the supervisory operator,

and line relay 300 is operated a corresponding number of times. These impulses are repeated from ground on armature 301 and its back contact, armature 306 and its front contact, winding of relay 310, front contact and armature 316 of operated relay 315, back contact and armature 321, through the winding of the stepping magnet 330 to battery. Stepping magnet 330 energizes and deenergizes four times in succession and steps the wiper 333 of the control switch S2 onto its fourth bank contact to which conductor 385 is connected. When the calling device CD rotates back to normal the impulse springs remain closed thereby maintaining relay 300 energized. A short time afterward relay 310 deenergizes and at its armature 311 and its front contact removes ground by way of armature 318 and its front contact, from one side of the upper winding of relay 320 and this winding then energizes in series with the lower winding, from ground on armature 307 and its front contact to armature 322. At armature 321 and its back contact the circuit for stepping magnet 330 is interrupted, while the original energizing circuit for the first step of relay 320 is opened at armature 323. At the off-normal springs 332 which were operated when the wiper 333 took its first step, the circuit for the release magnet 331 is prepared, from ground at armature 307 of relay 305 which is maintained energized as long as relay 300 has its circuit closed. Relays 315 and 320 likewise are locked energized from ground on armature 307 and their locking armatures 317 and 322, respectively.

After the supervisor has transmitted the twodigit number 64 she may wish to attend to other duties while the patrol line PL is being signaled by the equipment of Fig. 3. She therefore restores the key K-4 to normal while maintaining key K5 operated to complete the loop circuit over conductors and 71 for relay 300 by Way of normally closed springs 57 and 59 of key K-4 and springs 60 of key K5. Relay 300 thereby remains energized as long as key K5 is operated.

Referring now to the code sender switch CS of Fig. 3, after the second digit 4 of the signaling number has been transmitted from the calling device CD and two-step relay 320 is operated, ground from its front contact and armature 319 is extended through the winding of relay 375 to batlery. Relay 375 upon operating at armature 378 and its back contact opens a point in the circuit for wiper 383; at front contact and armature 374 a shunting circuit for relay 370 is prepared. At armature 379 and front contact the circuit for relay 370 is prepared, while at front contact and armatm'e 376 ground is connected through front contact and armature 377 to the wiper 382. A branch of the above circuit extends from ground on armature 376 and its front contact, over conductor 337, armature 381 and the back contact of the rotary magnet 380, armature 372 and the back contact, through the Winding of sloW-to-energize relay 350 to battery. The high resistance in shunt of the winding of relay 350 and the other resistance in shunt of relays 355 and 360 are for the purpose of preventing accessive sparking of the contacts at armature 381. Relay 350 after an interval closes its armature 351 to its front contact and extends the ground from armature 376 by way of this armature and its front contact, through the winding of the rotary magnet 380 to battery. The high resistance in shunt of the rotary magnet 380 of this circuit is for the purpose of preventing accessive sparking at the contacts of armalure 351. The rotary magnet 330 upon energizing at its armature 381 and the back contact interrupts the energizing circuit for relay 350 which slowly restores its armature 351. Relay 350 upon deenergizing opens the circuit for the rotary magnet 380 at its front contact and armature 351, and the rotary magnet 380 upon deenergizing advances the wipers 382 and 383 of the code sender one step in a forward direction as indicated by the arrows and onto the first set of bank contacts.

The wiper 383 is not effective at this time due to the energization of relay 375 which holds the circuit of the wiper open at armature 378 and its back contact. As the first contact in the bank of wiper 382 is not connected to a conductor upon which wiper 328 of the control switch S1 is resting, no change in the operation of the code sender CS occurs at this time. As soon as the rotary magnet 380 completely deenergizes it closes its armature 381 on its back contact and again completes the circuit for the slow-to-energize relay 350, by way of armature 372 and its back contact from ground on armature 376. Relay 350 attracts its armature 351 and again completes the circuit for the rotary magnet 380 from ground on armature 376. Rotary magnet 380 upon energizing opens the energizing circuit for the slowto-pull-up relay350 at back contact and armature 381. Relay 350 after an interval deenergizes and opens the circuit for the rotary magnet at its front contact and armature 351. This continued alternate energization and dcenergization of the rotary magnet and the slow-{o-energize relay 350 continues and each time the rotary magnet 380 deenergizes it advances the wipers 382 and 383 in a forward direction onto the next set of bank contacts.

When wiper 382 engages the bank contact to which conductor 384 is connected, a circuit is completed extending from ground on armature 376 and its front contact, front contact and armature 377, wiper 382, the bank contact upon which it is now resting and to which conductor 384 is connected, over conductor 384, the sixth bank contact of the control switch S1 upon which wiper 328 is now resting, conductor 335, armature 379 and its front contact, through the winding of relay 370 and the non-inductive resistance 367 to battery. Relay 370 upon energizing operates its armature 371 to its front contact and completes a locking circuit for itself over these contacts, to ground on armature 376. At armature 372 and its back contact the original circuit for energizing relay 350 is interrupted, and at the front contact of this armature a new slow-operating circuit for rotary magnet 380 is prepared. At the front contact of armature 373 a circuit for slow-release relay 365 is prepared and a branch of this circuit extends through the winding of the generator control relay 390 to battery. The lamp L8 is connected in parallel with this circuit and is for the purpose of visibly indicating to the supervising operator the code number which is being transmitted to signal the patrolman on the patrol line PL and in order to serve as a check that she has transmitted the correct number.

The ground from front contact and armature 376 now extends over conductor 337, armature 331 and its back contact, armature 372 and its front contact, back contact and armature 366, through the winding of slow-to-energize relay 360 to battery. At front contact and armature 361 relay 360 after an interval energizes and closes a circuit from the ground on armature 376, through the winding of slow-to-energize relay 355 to battery. Relay 355 after an interval energizes and closes its front contact on its armature 356 to complete the circuit through the winding of relay 350, and this relay upon energizing at its front contact and armature 351 completes the circuit for the rotary magnet 380 over conductor 337. The rotary magnet 380 upon energizing closes its armature 361 onto its front contact and completes a circuit for relays 390 and 365 in parallel, over a circuit from ground on armature 376, conductor 337, front contact and armature 381, armature 373 and its front contact, through the winding of relay 365 to battery; a branch of this circuit extending through the windin of relay 390 to battery and also in parallel with the lamp L-8. Relay 396 upon energizing, closes its front contact on its. armature 391 and connects the generator G2 to the common conductor for a purpose which will later on be pointed out. Relay 365 upon energizing, opens the circuit for slow-to-energize relay 360 at its back contact and armature 366. Relay upon deenergizing, opens the circuit for relay 355 at its armature 361, and relay 355 upon likewise falling away opens the circuit for relay 35-0 at armature 356. Relay 356 upon deenergizing, after a short interval interrupts the circuit for the rotary magnet 330 at its armature The rotary magnet upon deenergizing adces the wipers 332 and 333 in a forward diction onto the next set of bank contacts. At its back contact and armature 331 the rotary ;-agnet again completes the circuit for the first of the slow-acting relays 360, while at the front contacts of armature 331 the circuit for slowrelease relay 365 and ringing relay 3% is disconnected. Relays 360, 355 and 356 are again energized in succession, and relay 356 upon opcrating, again closes the circuit for the rotary magnet 330 as before. The rotary magnet upon operating at its armature 381 again completes the circuit for relay 365 and relay 390, and in parallel with this circuit, the lamp L8. Relay 365 again opens circuit for the slow-to-pull-up relay 363 a its armature 366, and when the last of these relays, relay 356, has restored its armature 351 the rotary magnet circuit is again opened so that the wipers 382 and 383 are again rotated onto the next set of bank contacts.

The above series of operations continue with the rotary magnet 380 stepping the wipers 382 and 363 at a slow rate of speed over the bank contacts, and each time the rotary magnet energizes th wipers take one step, relay 390 and connects the generator G2 to the common conductor 75. This action continues wiper 382 encounters bank contact 386. ng this interval the generator (Ii-2 has been projected upon the common conductor 75 six times in succession in accordance with the first ii of the signaling code number 64.

When wiper 382 encounters bank contact round from armature 376 is extended through rmature 377, wiper 332, bank contact 386 and e conductor which is connected to it, conductor 34, armature 374 and its front contact, through .1116 non-inductive resistance 367 which is in shunt of relay 370. As a result of this relay 376 is shunted by the resistance 367 and ground on the other end of its winding and is deenergized. At armature 371 and its front contact relay 379 opens its locking circuit, and at armature 373 opens the was circuit for the ringing relay 390, while at armature 372 and its back contact the comparatively fast operating stepping circuit and interrupting circuit between the rotary magnet 380 and slowto-pull-up relay 350 is again completed. Ground is now extended from armature 376 as before, over conductor 337, armature 331, armature 372, through the winding of relay 356, to battery. Relay 350 upon energizing, at its armature 351 completes the circuit for the rotary magnet 380 which upon energizing interrupts the circuit for relay 350 at armature 331 and this relay in turn opens the circuit of the rotary magnet at armature 351. Consequently the rotary magnet 380 steps the wipers 382 and 383 onto the next set of bank contacts. The above interval comprises the time interval between the two digits of the signaling number 64 and will be the same for any other number which may be transmitted by the operator. Wiper 382 thereby comes to rest upon bank contact 387 and completes the circuit for relay 370 again, from ground at armature 376, armature 377, Wiper 382, bank contact 387, conductor 335, armature 379 and its front contact, through the winding of relay 370, and the resistance 367 to battery. Relay 370 upon operating, completes a locking circuit for itself at armature 371 from ground at armature 376; at armature 373 and its front contact, the circuit for relay 365 and ring ing relay 3% is again prepared; while at armature 372 and its front contact the group of slowoperating relays 350, 355 and 360 are again enerized in succession and when the last one operates it completes the circuit for the rotary magnet 380 to step the wipers onto the next set of bank contacts.

In the above manner the rotary magnet 386 is again operated at comparatively slow intervals and at each operation the relay 390 operates its armature 391 to project the generator G2 upon the common conductor 75. This action continues until the rotary magnet 380 steps the wiper 332 upon the bank contact to which conductor 385 is connected and during which interval the generator G-2 will have been projected upon the conductor 75 four times in succession, corresponding to the second digit of the number dialled by the supervisor. When wiper 382 encounters the bank contact upon which conductor 385 is connected, ground from armature 376 and its front contact is extended over armature 377 and its front contact, wiper 332, bank contact on which conductor 335 is connected, the fourth bank contact of the control switch S2 upon which wiper 333 is now resting, conductor 33 i, 1:

armature 374 and its front contact, resistance 367 to battery in shunt of relay 370. Relay 370 consequently deenergizes and at its armature 371 opens its locking circuit, and at armature 3'73 disconnects relays 365 and 390 which thereupon deenergize. At the back contact of armature 372 the comparatively fast stepping circuit for the rotary magnet 380 is again completed which is controlled by the slow-pull-up relay 359. This relay and magnet 330 alternately energize and deenergize to step the wipers 382 and 333 at a comparatively fast rate of speed over the bank contacts. The last three multiple connected contacts over which wiper 382 will rotate are for the purpose of assuring that the relay 370 will be deenergized before the wiper commences to start over again in rotating over its bank contacts the second time.

After wiper 382 has made a complete revolution of its bank contacts the comparatively fast stepping operation of the switch will continue until the wiper 382 encounters the contact to which conductor 384 is connected, whereupon as has been previously described the code sender operates at a slow rate of speed to control relay 390 and again connect the generator G-Z to the common conductor '75.

The above operation of the code sending switch CS continues indefinitely and the signaling number 64 set up by the supervising operator is there by transmitted any number of times in succession, until the patrolman at the station PL responds to the signal as will be pointed out later. The supervisor upon being aware that the call has been answered restores the key K5, thereby opening the springs 60 which open the circuit for the line relay 300 extending over conductors 70 and 71. Role 300 upon deenergizing at its armature 301 opens the circuit for slow-release relay 305. Relay 305 upon restoring after an interval at armature 3c? and its back contact connects ground through the off-normal springs 32'! and 332 to the windings of the release magnets 326 and 331 of the switches S1 and 8-2. These release magnets upon energizing release the wipers 328 an 333 so that they will restore to their normal position under the action of a retracting spring. As soon as the wipers have reached their normal position the off-normal contacts 327 and 332 will open and the release magnets 326 and will deenergize. At the front contact of armature 307 the locking circuit for relays 315 and 320 extending to their front contacts and armatures 317 and 822 will be interrupted and these relays upon restoring will release their armatures. Relay 320 upon restoring armature 319 opens the circuit extending over conductor 336 through the winding of relay 375. Relay 3'75 upon restoring disconnects the controlling ground from armature 3'76 and its front contact extending over conductor 337 to stop the rotary operation of the code sender CS, regardless of the position of the code sender at time the release is eilected. If relay 370 has been operated at this time its locking circuit will be interrupted.

If the wipers 382 and 383 are not in their normal position at this time, wiper 383 will pick-up a ground connection from any of contacts upon h it may be resting and extend this ground through the back contact of armature .373, back contact and armature 371, conductor 337, armature 381 and its back contact, armature 3'72 its back contact, through the winding of rJ-to-p up relay 350 to battery. Relay 350 upon ener g at its armature 351 and its front contact the same groimd through the winding of rotary magnet 380 to battery. The rotary magnet at its armature 381 upon energizing i i the circuit for relay 350. This alternate ation. and deenergization of the rotary net and relay 350 continues and the wipers across the bank contacts until wiper i 's its last ungrounded bank contact, wh reupon the switch will stop in its normal po- Referring now to Fig. l, the patrolman on the patrol line PLs signaled in accordance with the signaling code 64 transmitted by the supervising operator time generator G-2 is connected to the conductor 75 from armature 392 by relay 390. This generator current extends over conductor '75. through the lower winding of ringing relay 20. ha contact and armature 32 of relay 30, contact springs 43 and 42 of operated key K-7, normally closed contacts 22 of relay 20,

line conductor 3, condenser '7, through the winding of relay to ground. The other side of the circuit extends from ground on armature springs 44 and 4 of key K-l, contacts 26 to conductor 2. Relay does not energize from the source of alternating current from the generator G-2 but the relay 5 which is an alternating current relay does energize, and at its front contact and armature 6 connects the battery BA to the lamp L1. This battery BA may be a local source of direct or alternating current. The lamp Ll therefore is illuminated each time relay 5 is energized, which will be in accordance with the code number 64. In other words, the lamp will be lighted siX times in succession and then four times in succession as long as the code sender CS is operated.

The patrolman noting the illumination of the lamp in accordance with this code which may be his particular signal responds by removing his receiver R from the switch hook St. This closes a complete loop circuit across the line conductors 2 and 3, through the patrol line telephone, and when relay 390 disconnects the generator G2 from the common conductor '25, it connects battery from the back contact of armature 391 to conductor '75, lower winding of relay 20, back contact and armature 32, closed springs 42 and 43 of operated key K'7, closed contacts 22 of relay 20, line conductor 3, through the patrol telephone PL, back over conductor 2, closed contacts 26 of relay 20, spring 45 and ground on spring 44 of key K7. Relay 20 thereby energizes in this direct current circuit and at its front contact and armature 23 completes a locking circuit for itself from ground on springs 41 of operated ke" 3-4. At the front contact of armature 24 ground is connected to back contact and armature 33, through the lamp L to battery, to inform the supervisor that the patrolman has responded to his call signal. At armatures 21 and 25 relay 20 operates the contacts 22 and 26 to disconnect the key K7 from the patrol lines 2 and 3 and connect the line instead through the condensers 2'7 and 28 to the common conductors 46 and 4'7, which extend through key I Z-2 and key 31-3 and over conductors 6'7 and 68 to the supervisors telephone set OP. Relay 3D likewise energizes over the loop circuit and the line conductors 2 and 3 and at armature 31 completes a further point in the locking circuit of relay 2 3. further point in the ringing circuit of conductor '75 is opened, while at front contact and armature 33 the lamp L--2 is disconnected and the supervisor may now restore the key K--7. The supervisor may now converse with the patrolman on the line PL and give him the necessary instructions, talking battery for the patrol line being furnished from relay 33, while talking current for the operator's telephone circuit is provided through the windings of relay If instead of calling patrolman by means of the lamp L--l, the operator dos cs to signal him audibly, she may do so by operating t. e key K5 instead of the key EL -5. The circuit conditions are thereby est rs-" rod for operating the signaling means BL at patrol station as when the key K--'. was operated, with the exception that the common ringing conductor "(5 extends through the lower winding of relay 20, back contact and armature 32, springs 39 and 40 of operated key K-G, normally closed springs of key K7. normally closed contacts 26 of relay 20, condenser 8, through the winding of alternating current relay 1G to ground. The other side of the circuit extends from ground on springs 3'7 and At armature 32 a j,

38, normally closed springs 42 of key K-7, normally closed contacts 22, to the line conductor 3. Relay 16 upon operating closes its front contact on its armature 11 and connects the battery BA across the loud ringing bell BL. The bell BL thereby rings in accordance with the signaling code 64, for example.

When the patrolman responds to the call he removes. his receiver R which places a direct current loop circuit through the telephone instrument to cause the energization of relay 20 over the circuit from battery on the baci: contacts or" armature 391 to ground on spring 3'? as has been previously pointed out. The patrol line FL is now connected at contacts 22 and 26, directly to the operators telephone circuit.

It will be appreciated from the above description of the signaling of a patrolman on a particular line or station in accordance with a code assigned to that patrolman that any additional number of lines may be signaled at the same time by merely operating key K-6 or key K-l' and simultaneously signaling each of the lines in accordance with the same code. This is desirable when the supervising operator Wishes to signal a certain patrolman who is traveling a beat comprising more than one patrol station. In connection with this feature she may operate all of her signaling keys, K-G and I-7, and transmit general riot call to all lines in accordance with a special code which is known to all patrolmen as a riot call code. In this event they may all respond to this signal by reporting to their respective patrol stations and all be connected to the common talking conductors to and 47 whereby all of them may be instantly aware of any instructions which may be transmitted by the supervising operator. As each patrolman responds to the call his associated lamp, such as L-Z, will become illuminated to inform the supervisor that the patrolman has responded.

From the above description it will be seen that a novel and efficient police signaling system has been designed requiring a minimum amount of equipment for signaling the patrol lines and having means for establishing various connections under control or" the supervising operator. While this system has been described in connection with a police signaling system it is equally applicable to any other type of signaling systems, such as a Watchmans system, and it is therefore not desired to be limited to the specific embodiment illustrated and described, but only to the extent of the appended claims.

What is claimed is:

1. In a signaling system, a supervising office, a plurality of lines connected to ofiice, visible and audible call signals on each of said patrol lines, a source of alternating current at said central station, a circuit closer in said central station effective to connect said alternating current to one side of said line to operate said visible call signal and to the opposite side of said line to operate said audible call signal, a line signal at said central oilice individual to each of patrol lines, and means at said patrol line operated censequent to the response to either of call signals to retire the actuated call signal and to operate said line signal.

2. In a signaling system, a supervisory office, a plurality of two-conductor patrol lines connected to said central office, visible and audible call signals on each of said lines, a source of current at said central office, circuit closing means effective to connect said source of current to one side of said line to operate the audible call signal and effective to connect said current to the opposite side of the line to operate the visible call signal, means. manually controlled in response to said call signals eifective to short circuit said line, said source of current disconnected from said line responsive to said short circuit to deenergize said call signals, a line signal at said central oifice, and relay means effective responsive to said short-circuit to operate said line signal.

3. In a signaling system, a central supervisory ofiice, a plurality of patrol lines terminating in said central office, a plurality of different signaling devices on each or" said patrol lines, circuitclosing at said central oiiice to selectively operate any or said signalin devices on said patrol lines, means controlled from said patrol lines in pence lo said signals to disconnect said circuit-closi means from the line to deenergize said sign is devices, a line signal in said central oiiice individual to each or" said lines, said line signal operative responsive to the disconnection or" said signaling devices at said patrol lines and a supervisors telephone circuit in said central office automatically connected to said patrol iine responsive to the disconnection of said signaling devices.

4. In a signaling system, a central supervising ofiice, a plurality of two-conductor patrol lines terminating in said oflice, signals on each patrol line connected to opposite conductors of said line, a particular code assigned to each of said patrol lines, code generating means at said central oilice, said code-generating means operative to transmit a code assigned to a particular patrol line over one or the other side or" said line to selectively operate said signals in accordance with said code, said code-generating means operative to transmit said code a plurality of times in succession, and means controlled from said patrol line in response to the operation of said signals to disconnect said code-generating means therefrom and stop the transmission of said code over said patrol line.

5. In a signaling system, a central supervising oiiice, a plurality of patrol lines terminating in said oifice, code signaling and generating equipment at said central office, a plurality of signaling devices on each of said patrol lines, circuit-closing means at said central office effective to selectively connect any of said signaling devices on any patrol line with said code generating equipment, said code generating equipment operative to control said selected signaling device in accordance with a particular code transmitted over said patrol line, means controlled by a patrol man in response to the operation of said signaling devices to disconnect said code generating equipment from said line, said code generating equipment restored to normal upon its disconnection from the line.

6. In a signaling system, a central supervisory office, a plurality of patrol lines each comprising two conductors terminating in said central oifice, signals on each of said patrol lines, one of said signals being connected to one side of said line and the other signal to the opposite side of said line, code generating and signalingequipment at said central offioe for transmitting a code characteristic of any patrol line, connecting means in said central oflice for associating either of said patrol line signals with said code generating equipment, said code generating equipment operated a plurality of times in succession to control the selected signal on said patrol line in accordance with the individual code or" said line, a telephone connected to said patrol line, a telephone at said central supervisory ofiice, said code generating equipment disconnected from said patrol line and said supervisors telephone connected to the line responsive to the removal of the receiver of the patrol line telephone when said signal is responded to.

'7. In a signaling system, a central supervisory office, a plurality of patrol lines terminating in said ofiice, each of said lines comprising two conductors, a different signal on said patrol lines connected to each side of said lines, code generating and signaling equipment at said central oilice, connecting means at said central office for associating either of said signals on said patrol line with said code generating equipment, a different code assigned to each of said patrol lines, said code generating equipment operated in accordance with a code assigned to a patrol line for transmitting said code to said patrol line to operate the selected signal, a telephone circuit connected to said patrol line, a telephone circuit at said central oilice, said code generating equipment automatically disconnected from said patrol line and said central oflice telephone connected thereto to establish a telephone connection with said patrol telephone responsive to the removal of the receiver of the patrol line telephone when said code signal is answered, and means for restoring said code generating equipment to normal position after it is disconnected from said patrol line.

8. In a signaling system, a central ofiice, a plurality of patrol lines terminating in said oilice, a pair of diiferent signals at each patrol station, circuit-closing means controlled from said central ofiice to selectively operate either one of said signals in accordance with a particular code assigned to the instant station, controlling means at said patrol station operated by the patrolman in response to said signal for disconnecting said signal operating means from the line, a line signal individual to each line at said central oflice, said controlling means at said patrol station effective to operate said central office line signal in a certain manner when making an ordinary reporting call, other control means at said patrol station effective to operate said central ofiice line signal in a different manner when making a special call from said patrol line, and relay means effective responsive to the operation of said central oiiice line signal in either manner of operation for disconnecting said patrol station signals.

9. In a signaling system, a supervisory central office, a plurality of patrol stations connected to said central office, a pair of signaling devices at each of said patrol stations, code signaling and generating equipment at said central oflice, said code signaling and generating equipment operated at said central oilice in accordance with a code assigned to a particular patrol station, means including a switch at said central office for selectively associating either of said signals on said patrol line with said code signaling and generating equipment, said code generating equipment operating the selected signal in accordance with said particular code, switch hook means at the patrol station operated by said patrolman responsive to said signal and eifective to disconnect said code generating equipment from said patrol line, a telephone at said patrol station, another telephone at said central station, said patrol telephone connected with said central ofiice telephone responsive to the disconnection of said code generating equipment from said patrol line.

10. In a signaling system, a central oflice, a plurality of patrol stations connected to said ofiice, a pair of signals at each of said patrol stations, code transmitting and signaling equipment at said central oifice comprising a pair of control switches and a code sender switch, means includ ing a switch at said central office for associating either of said signals at said patrol station with said code signaling equipment, a particular twodigit code assigned to each of said patrol stations, circuit means controlled by the supervisor at said central station when calling a station for operating the first of said control switches in accordance with the first digit of the code and for then operating the second control switch in accordance with the second digit of the code, the operation of the second control switch effective to operate said code sender, said code sender eifective to operate the selected signal at the said patrol station in accordance with said transmitted code, and means including a switch hook at said patrol station operative to disconnect said code signaling equipment from said patrol line.

11. In a signaling system, a central oflice, a patrol station having a pair of conductors connecting it with the central office, a pair of keys and a line relay at said ofiice in which said conductors terminate, a pair of call signals at said station each connected to a separate line conductor, a line signal controlled by said line relay at said ofiice, means responsive to the operation of one of said keys for operating one of said call signals over one of the conductors and responsive to the operation of the other of said keys for operating the other of the call signals over the other conductor, and means at said patrol station operated by a patrolman in response to said call sig- 1' nals for disconnecting said call signals and for operating said line relay to operate said line lamp.

12. In a signaling system, a central ofiice, a patrol station having a pair of conductors connecting it with the central oifice, a pair of keys at said office one connected to each of said conductors, separate call signals connected to each of said conductors at said patrol station, code generating mechanism at said ofiice, the operation of one of said pair of keys effective to connect said code generating mechanism to one of said conductors to operate a certain one of said call signals and the operation of the other of said keys effective to connect the code generating mechanism to the other of said conductors to operate another one of said call signals, and means including a switchhook at said patrol station effective in response to said call signals to disconnect said code generating mechanism from said conductors.

OSCAR CHARLES LEVY. 

